1. Field of the Invention
The present invention generally relates to a height adjustable chair with rocking function, which is used as an office chair.
2. Description of Prior Art
A height adjustable chair with rocking function having a means for rocking a back plate (backrest) and a means for adjusting a height of a seat plate has a structure that, for example, as a chair disclosed in Japanese Utility Model Publication 6-26588, adjusts a height of a seat plate, namely adjusts an extension and contraction of a support leg to which a gas spring is internally fitted, by operating a button for advancing and retreating a rod of a gas spring with a pressing part of base end side of an operation lever protruding to the outside of a seat frame to which the seat plate is attached and adjusts, on the other hand, a cushioning property of the back plate (back frame) by adjusting a spring pressure of a rocking compression spring by vertically moving an adjustment plate by operating a knob of an adjustment screw protruded to a lower back side of the seat frame.